We examined bulk soil properties and molecular
biomarker distributions in surface soils from Inner Mongolian
grasslands in order to understand the responses of soil
organic matter to different land use. A total of 16 soils were
collected from severely degraded grassland by overgrazing
(DG), native grassland without apparent anthropogenic
disturbance (NG), groundwater-sustaining grassland (GG)
and restored grassland from previous potato cropland (RG).
Compared to NG, soil organic carbon content was lower
by 50 % in DG, but higher by six-fold in GG and onefold
in RG. The δ
13C values of soil organic carbon were –
24.2 ± 0.6 ‰ in DG, –24.9 ± 0.6 ‰ in NG, –25.1 ± 0.1 ‰
in RG and –26.2 ± 0.6 ‰ in GG, reflecting different degradation
degrees of soil organic matter or different water use
efficiencies. The soils in DG contained the lowest abundance
of aliphatic lipids (n-alkanes, n-alkanols, n-alkanoic acids,
ω-hydroxylalkanoic acids and α-hydroxyalkanoic acids) and
lignin-phenols, suggesting selective removal of these biochemically
recalcitrant biomarkers with grassland degradation
by microbial respiration or wind erosion. Compared to
NG, the soils in GG and RG increased ω-hydroxylalkanoic
acids by 60–70 %, a biomarker for suberin from roots, and increased
α-hydroxylalkanoic acids by 10–20 %, a biomarker
for both cutin and suberin. Our results demonstrate that the
groundwater supply and cultivation–restoration practices in
Inner Mongolian grasslands not only enhance soil organic
carbon sequestration, but also change the proportions of
shoot- versus root-derived carbon in soils. This finding has
important implications for the global carbon cycle since rootderived
aliphatic carbon has a longer residence time than the
aboveground tissue-derived carbon in soils.
We examined bulk soil properties and molecularbiomarker distributions in surface soils from Inner Mongoliangrasslands in order to understand the responses of soilorganic matter to different land use. A total of 16 soils werecollected from severely degraded grassland by overgrazing(DG), native grassland without apparent anthropogenicdisturbance (NG), groundwater-sustaining grassland (GG)and restored grassland from previous potato cropland (RG).Compared to NG, soil organic carbon content was lowerby 50 % in DG, but higher by six-fold in GG and onefoldin RG. The δ13C values of soil organic carbon were –24.2 ± 0.6 ‰ in DG, –24.9 ± 0.6 ‰ in NG, –25.1 ± 0.1 ‰in RG and –26.2 ± 0.6 ‰ in GG, reflecting different degradationdegrees of soil organic matter or different water useefficiencies. The soils in DG contained the lowest abundanceof aliphatic lipids (n-alkanes, n-alkanols, n-alkanoic acids,ω-hydroxylalkanoic acids and α-hydroxyalkanoic acids) andlignin-phenols, suggesting selective removal of these biochemicallyrecalcitrant biomarkers with grassland degradationby microbial respiration or wind erosion. Compared toNG, the soils in GG and RG increased ω-hydroxylalkanoicacids by 60–70 %, a biomarker for suberin from roots, and increasedα-hydroxylalkanoic acids by 10–20 %, a biomarkerfor both cutin and suberin. Our results demonstrate that thegroundwater supply and cultivation–restoration practices inทุ่งหญ้ามองโกเลียภายในไม่เพียงแต่เพิ่มดินอินทรีย์คาร์บอนอายัด แต่ยัง เปลี่ยนสัดส่วนของยิง-เมื่อเทียบกับคาร์บอนที่ได้มารากในดิน มีการค้นหานี้ผลกระทบสำคัญสำหรับวัฏจักรคาร์บอนทั่วโลกตั้งแต่ rootderivedอะลิฟาติกคาร์บอนมีเวลาพักนานขึ้นกว่าโผล่มาเยื่อคาร์บอนในดิน
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